U.S. patent number 5,090,126 [Application Number 07/556,990] was granted by the patent office on 1992-02-25 for rotary tool quick acting retention device.
Invention is credited to Toney D. Higgins.
United States Patent |
5,090,126 |
Higgins |
February 25, 1992 |
Rotary tool quick acting retention device
Abstract
A motor driven rotary tool machine having a drive shaft, an
outer end portion thereof having a shoulder thereon, a rotary tool
such as a saw blade having a substantially axially positioned
aperture, and a retention device for securely but readily removably
securing the tool on the shaft tightly against the shoulder means,
wherein the retention device includes the threaded bolt receiving
bore formed axially in the outer end of the shaft, a bolt mounted
through the aperture of the tool and having a shank threaded into
the bore, a stop on an outer end portion of the bolt spaced from
the tool, and a linearly slidable ramp piece interposed between the
tool and the stop and retentively forcing the tool against the
shoulder of the bolt.
Inventors: |
Higgins; Toney D. (Erwin,
TN) |
Family
ID: |
24223626 |
Appl.
No.: |
07/556,990 |
Filed: |
July 25, 1990 |
Current U.S.
Class: |
30/388; 144/238;
83/666 |
Current CPC
Class: |
B27B
5/32 (20130101); Y10T 83/9379 (20150401) |
Current International
Class: |
B27B
5/00 (20060101); B27B 5/32 (20060101); B23D
045/16 () |
Field of
Search: |
;30/388-391,347
;83/666,698-700,817,820 ;144/238 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Watts; Douglas D.
Claims
I claim:
1. A motor driven rotary tool machine having a drive shaft, an
outer end portion of said shaft having shoulder means thereon, tool
means having substantially axially positioned mounting aperture
means, and retention means for securely but readily removably
securing the tool means on said shaft tightly against said shoulder
means, wherein said retention means comprises a threaded bore
formed axially in the outer end of said shaft, bolt means mounted
through said aperture means and having shank means threaded into
said bore, stop means on an outer end portion of said bolt means
spaced from said tool means, and substantially linearly slidable
ramp means interposed between said tool means and said stop means
and retentively forcing said tool means against said shoulder
means, wherein said ramp means comprises a ramp block adapted for
linear movement and having side wall means lying adjacent opposite
sides of said bolt means, a ramp surface on each of said side wall
means and positioned adjacent the underside of said stop means on
either side of said shank means and adapted to slide against and
across said underside, each of said wall means having a
substantially planar base surface adapted to slidingly engage the
outer surface of a rotary tool as said ramp block is moved
generally linearly in a transverse direction with respect to the
axis of said bolt means, the linear movement of said ramp block in
one direction imparting generally axially directed force to said
underside of said stop means and to said outer surface of said
rotary tool.
2. The machine of claim 1 wherein washer means is interposed
between said base surfaces of said ramp block and said rotary tool,
wherein substantially parallel slot means are provided in the outer
face of said washer laterally on either side of the bolt aperture
therethrough, said base surfaces being positioned and slidable
within said slot means for imparting to and maintaining lateral
stability and correct positioning of said wall means.
3. The machine of claim 1 wherein said underside of said stop means
is bevelled at substantially the same angle with respect to the
bolt axis as the angle said ramp surfaces make with respect to the
bolt axis.
4. The machine of claim 1 wherein said ramp surfaces are provided
by slot means formed through each said wall means.
5. The machine of claim 4 wherein said stop means is provided on
opposite sides with first shoulder means slidably juxtaposed said
wall means, and with second shoulder means slidably mounted within
said slot means, said first and second shoulder means in
cooperation with said slot means providing a slidable but captured
bolt means.
6. The machine of claim 1 wherein said ramp surfaces are generally
inclined with respect to said base surfaces at an angle between
about two and eight degrees.
7. The machine of claim 1 wherein said ramp block is formed from a
substantially rectangular metal blank in which substantially mirror
image slot means are stamped out in the area of said wall means
lying on either side of a longitudinally extending web portion, and
wherein the blank is deformed along substantially parallel,
longitudinal lines to provide two substantially parallel walls
depending from said web portion, and wherein said slot means are
substantially opposite and parallel to each other in the formed
block.
8. The machine of claim 1 wherein said ramp means comprises a wedge
shaped, elongated block having elongated slot means therein for
slidably accomodating the shank of said bolt means.
9. The machine of claim 1 wherein contacting, sliding surfaces of
said block means and a substantially fixed position element of said
retention means are provided with cooperating ridge means adapted
for slidable interfitting and resisting relative motion
therebetween when said retention means is in its actuated
position.
10. The machine of claim 1 wherein said retention means comprises
generally transverse recess means in the outer end of said bolt
means, pin means mounted in said bolt means and extending
substantially laterally through said recess means, substantially
flat key means having ramp slot means transversely therethrough and
slidably mounted in said recess means with said pin means slidably
mounted through said slot means, whereby linear motion of said key
means in its actuated direction will engage a ramp surface of said
ramp slot with said pin means to tighten said tool means on said
drive shaft.
11. A rotary tool retention device for use on a motor driven rotary
tool machine, said machine having a drive shaft, an outer end
portion of the shaft having shoulder means thereon, rotary tool
means, bolt means having shank means and stop means, the shank
means being adapted to pass through aperture means in the tool
means and thread into threaded socket means in the outer end of the
shaft, the retention device being adapted for securely but readily
removably securing the tool means on the shaft tightly against the
shoulder means, said retention device comprising elongated body
means having generally longitudinally extending ramp surface means
and generally longitudinally extending base surface means, said
ramp and base surface means being spaced apart and angled with
respect to each other, one of said ramp or base surface means being
adapted to slidably engage the stop means of the bolt means, and
the other of said ramp or base surface means being adapted to
slidably engage the outer surface of the tool means, and impact
surface means on said body means having generally longitudinally
opposed generally transversely directed surfaces, said surfaces
adapted to be selectively struck with sufficient force to move said
body means in a desired longitudinal direction to selectively
tighten or loosen the tool means on the drive shaft.
12. The tool retention device of claim 11 wherein said body means
is elongated and provided with passage means extending
substantially longitudinally therethrough for slidably
accommodating the shank of said bolt means, said ramp surface means
comprising a ramp on either side of said passage means and adapted
to slidably engage said stop means.
13. The device of claim 12 wherein said ramps are provided by the
edges of a slot formed in each of two side walls of said body
means.
14. The device of claim 13 wherein said stop means projects through
said slots and is slidable therein.
15. The device of claim 11 wherein the contact surfaces of said
ramps are provided with friction increasing ridge means.
16. The device of claim 11 wherein said body means comprises a
flat, elongated key member having a generally longitudinal but
slightly upwardly angled slot therethrough providing said ramp
surface means.
Description
BACKGROUND OF INVENTION
1. Field of Invention
This invention concerns a device for retaining a rotary disc-like
tool such as a circular cutting blade, particularly a circular saw
blade onto the drive shaft of portable hand-held or stationary
machine wherein the device provides for quick connect and
disconnect of the blade or other tool to and from the shaft without
the need for wrenches or the like.
2. Discussion of Prior Art
Heretofore circular saw blades or other rotary tools including
grinding wheels, metal cutting rotary blades, abrasive wheels or
the like, all hereinafter referred to as blade means, or buffing or
polishing wheels or the like have been affixed to their drive
shafts by means of bolts as shown in U.S. Pat. No. 4,555,849, or by
special locking devices as shown in U.S. Pat. No. 4,706,386. In
each of these devices the blade means is removed by loosening and
removing a bolt or screw or the like which, of course, requires a
wrench and some means to hold the blade means against the rotative
force applied generated by the wrench. Both of these requirements
represent time delays and often effect physical injury such as
skinned knuckles or lacerated fingers.
Objects therefore of the present invention are: to provide a quick
connectable and disconnectable means for retaining a rotary
disc-like tool means onto its drive shaft; to provide such device
which requires the simplest of physical manipulation to affix the
tool means or to remove it from the shaft; and to construct such
device with structural design which provides an exceptionally high
degree of operational safety.
SUMMARY OF THE INVENTION
These and other objects hereinafter appearing have been attained in
accordance with the present invention which is defined in its
operative assembled aspect as a power operated rotary tool machine
having a drive shaft, an outer end portion of said shaft having
shoulder means thereon, tool means having axially positioned
mounting aperture means, and retention means for securely but
readily removably holding the tool means on said shaft tightly
against said shoulder means, wherein said retention means comprises
a threaded bore formed axially in the end of said shaft, bolt means
mounted through said aperture means of said tool means and having
shank means threaded into said bore and having outer stop means
spaced from said tool means, and substantially linearly operable
ramp means interposed between said tool means and said stop means
and retentively forcing said tool means against said shoulder
means.
GENERAL DESCRIPTION OF THE INVENTION
The present retention device as defined above utilizes the concept
of a ramp, which terms as used herein includes cam, to provide the
mechanical advantage needed to hold the blade against the shoulder
means on the shaft with sufficient force to prevent it from
rotating thereon. It is noted that the commonly employed retaining
bolt for securing circular blades to their shafts is, in a sense, a
ramp device since the threads thereof are inclined to the
horizontal. It is noted that the bolt as shown may be a threaded
drive shaft provided with a nut in place of the bolt head. The
present invention resides however, in the type of force necessary
to tighten or loosen the ramp mechanism. In the use of a thread
type ramp the force is obviously rotationally applied, whereas with
the present device the force is applied in a simple linear
direction. The threaded devices thus require the application of a
counter rotative force thereto in order to be loosened or tightened
which means that the blade must be held stationary, usually by the
application of force through the use of a hand held blade stopper
such as a screw driver or block of wood. Even then, proper
tightening of the bolt which requires a wrench is often difficult
and loosening of it to change the blade can be extremely vexing.
With the present linear ramp device however, a single hand wielding
any instrument capable of delivering a slight blow to the device is
essentially all that is required for changing the blade, and the
need for a wrench and blade stopper, and the use of two hands is
eliminated.
DETAILED DESCRIPTION OF THE INVENTION
The invention will be further understood from the following
description and drawings wherein:
FIG. 1 is a side view of a circular saw embodying the present
retention device shown enlarged and with portions broken away for
clarity;
FIG. 2 is an enlarged partial cross-sectional side view of a
variation of the retention device embodiment of FIG. 1 in its
untightened position;
FIG. 3 is a cross-sectional view of the retention device of FIG. 2
taken along line 3--3 of FIG. 2 in the direction of the arrows:
FIG. 4 is a partially cross-sectioned side view of a variation of
the retention device;
FIG. 5 is a view taken along line 5--5 of FIG. 4 in the direction
of the arrows;
FIG. 6 is a side view, partially in section, of the retention
device of FIG. 1;
FIG. 7 is a perspective view of the device of FIG. 6 taken along
line 7--7 thereof in the direction of the arrows;
FIG. 8 is an elevational view of a sheet metal blank for the
manufacture of the device of FIG. 7;
FIG. 9 is a cross-sectional side view of another variation of the
retention device;
FIG. 10 is a cross-sectional view taken along line 10--10 of FIG. 9
in the direction of the arrows; and
FIG. 11 is a top elevational view of the retention device of FIGS.
9 and 10 .
Referring to the drawings which are illustrative only and not drawn
to scale, and wherein the same numbers are used in the several
figures to identify the identical or equivalent structural elements
or features, a typical circular saw generally designated 10 is
shown on which the present retention device generally designated 12
is positioned to frictionally secure the blade 14 to the drive
shaft 16 which shaft is shown in FIGS. 3 and 4. The shaft and
retention device are shown enlarged in some figures for purposes of
clarity. The saw is provided with customary handle 18, trigger
switch 20, upper blade guard 22, lower retractable blade guard 24
and adjustable work contacting platform or base 26. A typical saw
is shown, for example, in U.S. Pat. No. 4,555,849, the disclosure
of which is incorporated herein by reference.
Referring further to the drawings, the rotary tool, which term is
used herein to include conventionally employed washers and the
washer described below, is frictionally held against the shaft end
28 (see FIGS. 3, 4 and 6) or equivalent shoulder means on the shaft
which may, e.g., be set back slightly from the end thereof, by
means of the present retention device, one embodiment thereof being
shown in FIGS. 6-8 in an assembly context comprising a wedge or
ramp block 30, bolt means 32 having threaded shank 34 and head or
stop 36, grooved washer 38 or equivalent having bolt aperture 39,
saw blade 12, and saw drive shaft 16 having a threaded, bolt
receiving bore 17.
Referring to FIG. 6, the relative positions of all of these
elements is such that a tap with any tool, e.g., the handle of a
screwdriver, against end 40 of the block will force upwardly
slanting ramps 42 further underneath bolt head 36 or a washer means
thereunder and lock blade 12 very tightly against end or shoulder
28 of the shaft. It is particularly noted that the inwardly
directed edge surfaces or bases 44 and 46 of the ramp block slide
in guide grooves 48 in the washer and are thus prevented from
spreading such as might reduce the compressive force against the
blade. The angle or slant that the ramps of any of the embodiments
shown herein makes with the base surfaces of the ramp block can be
widely varied, e.g., between about 0.5 to about 25 degrees since
once the bolt means had been finger tightened, a very slight
movement of the block will provide the necessary compressive force.
The bolt head 36 is shown as a conventional, off-the-shelf one,
however, the contact underside 50 thereof may be machined slanted
to lie flat against ramps 42 such as to effect a more mechanically
perfect ramping action.
In manufacturing the ramp block 30, a steel blank 52 may be
employed with the ramp slots 54, 56 stamped therethrough. Bending
of the blank at right angles along the dotted lines with bolt head
in place will form the block shown in FIG. 7. It is noted that the
dimensions shown in FIG. 8 wherein "BD" designates the bolt
diameter are exemplary only and can be varied according to the type
of blade and shaft involved. It has been found that the dimensions
shown, wherein the steel thickness is between about 0.08 and 0.2
inches is quite satisfactory, however, depending on the type of
material employed therefor, this thickness can be varied.
Similarly, the slant of the ramps shown in FIG. 8 has functioned
without fault, with absolutely no tendency for the block to retract
from its high pressure position during rigorous use of the circular
saw.
Referring to the alternative embodiment of FIGS. 2 and 3, the ramp
block 58 is formed essentially up-side-down from block 30 such that
its base 60 may contact the saw blade and thus eliminate the need,
or at least desirability, for a separate washer. A passage 62 in
the base slidably accommodates the bolt shank. In this embodiment,
a modified bolt head 64 is shown as being machined to closely but
slidingly fit between the block sides 66, 68 and having slanted
segments 70, 72 slidably mounted through the ramp slots 74, 76
respectively. This structure provides a very convenient handle
means for rotating bolt 32 to and from its intermediate or barely
loosened position from which the bolt can easily be finger rotated
to remove it, or finger rotated to slightly tighten the
blade/retention device assembly in preparation for actuation of the
device by striking the end 40 of the block.
Referring to the embodiment of FIGS. 4 and 5, the slidable ramp
block 78 and fixed washer 80 are provided with cooperating or
mating ridges 82, 84 respectively of any suitable dimensions and
slidable configuration, across which the block can frictionally
slide by impact force applied against its ends 86 or 88 to loosen
or tighten the assembly respectively. Washer 80 is preferably
rectangular and of about the same width as block 78. It is noted
that in all of the embodiments shown, it is preferred that the bolt
32 does not bottom out in bolt bore 17 in the shaft 16 as the bolt
is finger tightened to the aforesaid intermediate position,
otherwise the ramp block may not be sufficiently long to completely
tighten the assembly.
Referring to the embodiment of FIGS. 9-11, the ramp block is in the
form of a key 92 of hardened steel or the like provided with slot
94 and ramp surface 96. The bolt head is formed with a recess at 97
and provided with a pin 98 also of hardened steel or the like
passing though slot 94 and pressed into pin bearing aperture 100 in
the bolt head. It is preferred that washer 102 be used and provided
with slots 104 in which key 92 can slide to cam the assembly
against pin 98 to a tightened position.
It is noted that the structural features of any of the various
embodiments shown can be used to modify the other embodiments for
whatever advantage one may desire. For example, the ridges 82, 84,
or any equivalent thereof, shown in FIG. 4 can be incorporated in
any of the ramp surfaces shown. The materials of construction are
typically metal, preferably hardened or stainless steel, however,
tough plastics such as cellulose acetate butyrate may be
employed.
The invention has been described in detail with particular
reference to preferred embodiments thereof but it will be
understood that variations and modifications will be effected
within the spirit and scope of the invention.
* * * * *